| Photosynthesis in its simplest description is the biological process of turning energy from light into the chemical energy required for growth and reproduction. As fundamental and efficient as photosynthesis may be, under certain conditions such as high light or cold temperatures, the photosynthetic complex is easily damaged and may cause excessive cellular damage through the production of oxidative radicals. As a result, many organisms, such as cyanobacteria, have developed protective mechanisms to regulate the synthesis, arrangement, or activity of the various protein components which comprise the photosynthetic complex and how the energy derived from it is processed. The goal of this work is to characterize how one cyanobacterium, Synechocystis PCC6803, responds to the physiological stress inflicted by sudden and long term exposure to a high salt environment. Emphasis has been placed on identifying how Synechocystis PCC6803 optimizes energy metabolism in order to survive.;This document describes the logic and execution of a strategy employing the coordinated use of genomic sequence with standard molecular biology techniques and direct physiological measurements of photosynthetic parameters. This strategy was developed to monitor the physiological and transcriptional response of Synechocystis PCC6803 after salt shock until the culture has completely acclimated to high salt conditions. In short, this work attempts to identify, describe, and explain the series of events/responses which occur after salt treatment. These events include the temporal regulation of photosynthetic activity, enhanced cyclic electron transport around photosystem I, and increased superoxide production. Other responses which are not necessarily related to the bio-energetic network include the specific regulation of chaperonins, proteases, known stress responsive genes, several regulatory genes, and a long list of relatively uncharacterized genes. |
